In¯uence of co-cations on biosorption of lead and zinc ± a comparative evaluation in binary and multimetal systems

The in¯uence of co-cations (cadmium, copper, cobalt and nickel) on lead and zinc biosorption by Streptoverticillium cinnamoneum and Penicillium chrysogenum in binary and multimetal systems was evaluated. The metal sorption capacity of S. cinnamoneum was higher than P. chrysogenum for all the metals tested. Both the biomasses exhibited preferential uptake of lead in a multimetal situation. Even though mutual inhibition was seen for all binary systems containing zinc, systems containing lead exhibited unequal inhibition. The extent of metal sorption was dependent on metal chemistry, anity for binding sites and the type of metal binding. In multimetal systems, S. cinnamoneum and P. chrysogenum exhibited preferential sorption orders: Pb2‡ > Zn2‡ =ˆCu2‡ > Cd2‡ > Ni2‡ > Co2‡ and Pb2‡ > Cu2‡ > Zn2‡ > Cd2‡ > Ni2‡ > Co2‡. The order of metal biosorption in a multimetal system could be predicted well on the basis of Langmuir parameters evaluated in binary metal systems